Zimbra NE backup by CommVault - best practice & strategy

Gentlemen:
This may be long to read on though any help is appreciated.

Newbie I am in Zimbra. Came from MS Exchange way of administering mail stuff. Admiring all the straightforwardness of several backup schemes here for Zimbra, may I ask for the following for at least good practices if not the best ones for those who are implementing or had implemented similar for such. Can we create a sub-group just for this? Because, I know for sure there will be a lot more in the future. After which, as giving back, I myself am willing to share whatever we have here (and more) to the future newbies in Zimbra NE or even OpenSource. Thanks in advance Amigos.

1. Zimbra NE inherent style of backing up is in place going to a cheap NAS the huge 1TB data.

I would also look, as my reference to attain my objective, that Sample Backup Timeline written in p214, Zimbra CS NE Administrator's Guide R7.1 , c.May2011.

2. Considering all of the redologs & LDAP files for incremental backups, what else I am to consider?
3. Zimbra NE Details:
3.1 I have two hosts, ZMS001 is my mailbox, spell, mta,etc while ZMS002 is for other remaining services (eg. antispam, antivirus,etc)

ONLINE daily and weekly backups
And since I have the /opt/zimbra/backup in my ZMS001, the following I would do leaving ZMS002 out of the picture (am I right?):
3.2 I would have to backup everythng except /opt where Zimbra is.
3.3 I would to adjust the Zimbra backup policy not to backup as often (to reduce disk usage to /opt/zimbra/backup)
3.4 I would backup /opt separately (with a few of exceptions in there)
3.4.1 I would exclude /opt/zimbra/store from this /opt backup
3.5 I would of course have the /opt/zimbra/redolog/ backed up
3.5.1 I would then back this redolog up as often, say every two hours
3.5.2 I would test this if this is doable and policy-driven it may be in CommVault
3.5.3 Would the redologs be purged automatically? (pardon me for this)

3.6 Then I would backup /var/log daily and even retain that for as long as possible.
3.7 Then of course backing up those in the normal Zimbra's backup directory (eg accounts.xml, etc)
3.8 I would also backup /opt/zimbra/log daily

4. CommVault Details:
4.1 I'm to be using an agent from CommVault called iDataAgent for Linux FS which I intend to install to ZMS001.
4.2 Backing up to generously huge space for now. And backing it up soon in tapes.
4.3 I would NOT install default location; instead to the ff:
4.3.1 (Commvault) Simpana binaries at /usr/local/simpana to keep /opt for Zimbra solo room
4.3.2 /var/log/simpana/logfiles/ for its logs

How would often then I do an offline backup if I can or is it applicable?

On a separate note, if not too much for you, do you guys retain the dumpster in Zimbra? And if you do, how do you do retention- how many days? I have 260GB of it, whoooahhh! I love my users

Lastly, I could not forget Exchange whenever I do things in Zimbra. Nevertheless, I intend to combine what I know and to the best just like you all are
Cheers,